Absorbing properties and structural design of microwave absorbers based on W-type La-doped ferrite and carbon fiber composites

Sol-gel method was used to prepare W-type BaCo2Fe16O27 hexaferrite and La-doped Ba0.7La0.3Co2Fe16O27 hexaferrite. Electromagnetic parameters of the ferrites and short carbon fiber composites were measured, and reflectivity was calculated according to transmission-line theory in the range 12.4-18 GHz. The results show that reflection loss of the doped ferrite composite is higher as compared to the no doped ferrite composite. Based on the above calculation, double-layer absorbers containing La-doped ferrite and carbon fiber composites were designed, and reflectivity of the double-layer absorbers made of different thickness and composition was calculated. Finally, a kind of structural absorber having excellent absorbing properties was achieved, and the bandwidth of the reflection loss less than -10dB can reach 5.2GHz in the range of 12.4-18 GHz. (c) 2005 Elsevier B.V. All rights reserved.